There are many types of heavy equipment in current use. For the purposes of this application heavy equipment is de, fined as power equipment for moving earth which includes a body containing a power source such as a diesel, gasoline or electric motor, a means of movement such as wheels or tracks connected to the power source, and a tool such as a movable blade or bucket attached to the body. Common names of such heavy equipment include bulldozer, loader, back hoe, and grader.
The different names relate to the blades and uses of the various types of heavy equipment. A bulldozer for example commonly includes a relatively fiat blade and tracks. In operation the blade is used to push material forward or to one side by tilting the blade. The blade can also be raised or lowered as well as rotated. Bulldozer blades commonly include a plurality of teeth on the lower edge of the blade to aid in digging. A bulldozer blade can also be used on a wheeled vehicle.
In a front end loader the blade is concave and is often called a bucket. In operation a front loader lowers the bucket to a digging position and advances forward. Material is then entrapped in the bucket which is next raised. The bucket may be rotated upward in this operation to prevent spillage. The bucket is finally rotated downward into the dump position to release the entrapped material.
A back hoe also includes a bucket. In a back hoe the bucket is usually mounted at the rear of the vehicle. The motions of the bucket are different than in a front loader and forward motion is not used to entrap material in the bucket. In a back hoe the bucket is rotated into the material sought to be removed from the dump position to a loaded position. The bucket is then raised upward with the material contained inside. The loaded bucket is commonly moved to one side and inverted to dump the contained material.
A grader blade is similar to a bulldozer blade but is usually used only at an angle to even or grade surfaces. Graders do not generally dump the material sought to be graded but rather move it to one side.
Each of the above types of heavy equipment may also be used for raking. Raking is a operation concerned with the removal of oversized material from a media. A common example would be the removal of construction debris from soil after a construction project. To use any of the above equipment for raking the blade or bucket is dismounted and replaced by a rake or a rake may be attached below the blade edge. The rake includes a plurality of teeth situated to dig into the soil. Material that is larger than the distance between the teeth is entrained when the rake is moved through the media. The material is next piled up by the rake for removal by another tool or burned in place.
A major disadvantage of raking in this manner is that the operation of attaching a rake is time consuming and somewhat difficult because both rakes and blades are heavy. When the rake is attached the equipment cannot be used for digging or loading. Since heavy equipment has a substantial hourly cost including that of the operator there has been a temptation to use the standard blades for raking tasks. The result has been generally unsatisfactory. For example if rake teeth are placed on the bottom edge of the bucket of a front loader or blade of a bulldozer the material sought to be raked tends to slide down off the edge of the bucket as one tries to pile the material up. In the case of a front loader the addition of raker teeth also impedes digging ability. Accordingly, there is a long-standing need to efficiently rake with equipment which can also be use for digging.